The document summarizes the key points from the book "A World on the Edge: How To Prevent Environmental and Economic Collapse" by Lester R. Brown. It outlines the goals of "Plan B" to stabilize the global population, eradicate poverty, restore the environment, and stabilize the climate. It warns that current trends of population growth, food demand, aquifer depletion and climate change threaten to push the world's systems past a tipping point. Immediate action is needed through increased energy efficiency, renewable energy and reforestation to avoid economic and social collapse.